## Filling an frame with Helium? Beware Silly post

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morrisond
Posts: 1075
Joined: Thu Mar 25, 2004 8:34 pm
The idea came to me from an following post about how far one would go for WW and someone mentioned tying balloons to an bike.

Instead of that with Carbon frames why not just inflate the bladders they use to make the frames with initially with Helium, but leave them in?

Could you get enough pressure in there to significantly reduce the weight of the bike?

Could we have our first sub 500 gram frame?

It should be relatively easy to pull the same trick with forks and handlebars/seatposts as well, just need an lining that is not porous to helium.

I know this is an very silly idea but has anyone tried it?

Anyone care to do the math on much lift you could get from the helium?

Could be an really neat trick in an UCI race as the bikes are probably only weighed at the end of the stage. Fill it with Helium race the stage and then release the helium prior to the line to get you back over the limit.

Theoretically you could get an even bigger benefit on Hot days as the frame heats up and causes the Helium to create more lift.

Just an crazy thought on an Wednesday afternoon...

morrisond
Posts: 1075
Joined: Thu Mar 25, 2004 8:34 pm
Scrap that idea, forgot that as pressure goes up lift goes down.

However if you filled it with Hydrogen you would get about 28g of lift for every balloon sized volume.

An frame with oversized tubes might hold what 4-5 balloons worth?

Well 100 grams is 100 grams....

CarlosFerreiro
Posts: 364
Joined: Thu Jan 08, 2009 1:41 pm
Location: Shetland, Scotland
Pumping everything out to leave a vacuum would be lightest....

Szczuldo
Posts: 571
Joined: Tue Aug 12, 2008 2:22 pm
Location: Salt Lake City, UT
CarlosFerreiro wrote:Pumping everything out to leave a vacuum would be lightest....

only thing to worry about then is the hair thick carbon fiber going to withstand atmospheric pressure.
My Lynskey R420 with Chorus 11

If you are interested in a Weight Weenies kit I no longer know what you should do.

JT_swe
Posts: 16
Joined: Wed Jan 10, 2007 8:40 pm
The lost weight for a vacuum filled frame would easily be added again by the amount of material needed to keep the frame gas tight and sealed. And the helium molecule is so small that it would leak through the frame/bags.

Redddraggon
Posts: 982
Joined: Thu Jul 24, 2008 10:59 pm
Location: North Wales
morrisond wrote:Could you get enough pressure in there to significantly reduce the weight of the bike?

Could we have our first sub 500 gram frame?

You're getting mass and weight confused. You can't decrease the mass of a frame by adding helium, weighed in grammes. However you could decrease the force caused by gravity, weight, measure in Newtons.

Therefore if you have a 900g frame, add helium, the frame will still be 900g, it'll just "weigh" less.